The Collaborative International Dictionary
Inefficacious \In*ef`fi*ca"cious\, a. [Pref. in- not +
efficacious: cf. F. inefficace, L. inefficax.]
Not efficacious; not having power to produce the effect
desired; inadequate; incompetent; inefficient; impotent.
--Boyle.
The authority of Parliament must become inefficacious .
. . to restrain the growth of disorders.
--Burke.
Note: Ineffectual, says Johnson, rather denotes an actual failure, and inefficacious an habitual impotence to any effect. But the distinction is not always observed, nor can it be; for we can not always know whether means are inefficacious till experiment has proved them ineffectual. Inefficacious is therefore sometimes synonymous with ineffectual.
Douglas Harper's Etymology Dictionary
1650s, from in- (1) "not, opposite of" + efficacious. Related: Inefficaciously; inefficaciousness (1640s).
Wiktionary
a. 1 Incapable of having the intended consequence. 2 Not effective.
WordNet
adj. lacking the power to produce a desired effect; "laws that are inefficacious in stopping crime" [ant: efficacious]
Usage examples of "inefficacious".
One desires to be alone to feed upon, at least in peace, the bitter food, the exasperating and inefficacious rancor against people and against fate, with which Gorka at that moment felt his heart to be so full.
Prussian gentleman on board our steamer, who was connected with that embassy, plainly indicated the disappointment felt at Berlin at the rather inefficacious nature of the diversion made in Venetia, and on the coast of Istria by the army and navy of Victor Emmanuel.
It is the chief torment of a person constituted as he was that strong as may be the determination to do a thing, fixed as may be the conviction that the thing ought to be done, no sooner has it been perfected than the objections of others, which before had been inefficacious become suddenly endowed with truth and force.
Cambridge receipt to be inefficacious, had sent him abroad to travel with a tutor.
And not only this, but, fourthly, the meaning of the doctrine itself will be in danger of being lost, or enfeebled, and deprived of its vital effect on the character and conduct: the dogma becoming a mere formal profession, inefficacious for good, but cumbering the ground, and preventing the growth of any real and heartfelt conviction, from reason or personal experience.
When he saw it was for joy I pounded him, he admitted he was Polyeidus and congratulated me on my achievement of Pegasus, which he was pleased to take for a sign that his petitions to Athene on my behalf had not been inefficacious.
Were the criminal law done away with in our present state of civilization, religion, ethics and civil procedure would be absolutely inefficacious to prevent anarchy.